A drive end block for a magnetron arrangement with a rotating target that has a simple design and is easy to maintain is described hereafter.
Magnetron arrangements with a rotating target are known in vacuum coating technology. With these magnetron arrangements, a target, usually tubular, surrounds a magnetic arrangement, such that the tubular target is rotatably mounted and drivable so that the target material is worn away uniformly. The tubular target is usually mounted between two end blocks in the vacuum chamber of a vacuum coating installation, said blocks being designed to allow rotatable mounting of the tubular target. In most cases, different functions are assigned to the two end blocks here. One of the end blocks is usually designed as a supply end block for supplying the magnetron with cooling water and electric power, and the other end block is designed as a drive end block for introducing a torque for creating the rotation of the tubular target.
Known drive end blocks therefore have an electromechanical drive mechanism in the form of an electric motor with gears, which introduces the torque via bevel gears, spur gears or toothed belts, for example. This drive mechanism must be potential-free and therefore must be installed so it is insulated with respect to the target and usually also with respect to the vacuum chamber. Therefore, with known drive end blocks, the drive mechanism is installed in the drive end block using insulators in such a way that the electric motor is usually outside of the vacuum chamber with respect to the atmosphere and a gear or parts of a gear or other torque transmitting mechanisms such as belt drives and the like are arranged inside the drive end block. Depending on the electric process voltage level, the cost of potential isolation can be enormous in order to reliably achieve the result that the process voltage applied to the tubular target does not arc over to the drive mechanism or the vacuum chamber. One example of such an end block is known from European Patent Application EP 1 365 436 A2.
Within the vacuum chamber, the torque is usually transferred from the drive mechanism arranged in the interior of the drive end block to the target in the vacuum chamber via an insulated coupling element. Since the drive end block combines the functions of initiating rotation, providing electric insulation and vacuum sealing, the components of the drive end block must be manufactured and installed with a high precision. Known drive end blocks have a very complex design in general and require a large number of individual parts to protect the seal of the vacuum chamber against the atmosphere and the electric insulation of the components accessible from the outside.